take into account specific characteristics of the summary data, the genetic architecture of the phenotypes, and the model to be specified. This can typically be achieved with simulation. Generally speaking, we would expect power to detect SNP effects on a common genetic factor to be high when the phenotypes composing the factor have high heritabilities, and high genetic correlations, sample sizes are larger and sample overlap is lower. That said, we still expect some power benefits relative to univariate GWAS when the constituent phenotypes are only moderately heritable and/or moderately genetically correlated and/or sample overlap is high. The choice of included summary statistics, phenotypes, and model(s) will of course depend on the researcher’s objectives and the model(s) to be specified.
